CHEAP, simple to prepare, a superb foil for the starchy, tender tastes of root vegetables, the virtues of the lamb shank have been rediscovered in recent years. The good news, however, is that its fashionability has not affected its price: the shanks still sell for half nothing in butchers' shops.

Slowly braised in cooking liquid, they yield relatively little meat, but what there is should be falling off the bone, and there should be an adequate gravy, for this is a dish that demands you mash your spuds into the sauce.

It was when mucking about with ideas for a sauce for lamb shanks that I first cooked them in a simple tomato sauce - the shank first browned on the outside in the pan in olive oil, then an onion sliced and fried until translucent, a chopped up tin of tomatoes poured in with some red wine and some water, a rosemary sprig tossed in, the whole lot covered and left for an hour in the top oven of an Aga.

I didn't want to cook the shank with root vegetables, however, so decided on fennel bulbs as an appropriate foil for the tomato sauce. It is easy to braise fennel, but a casserole should not require two cooking methods, so I simply quartered the bulbs and added them to the pot. About 40 minutes later, it was ready.

The aniseed of the fennel had been softened by cooking in the sauce, but the bulbs still had a crispness to them which is rather important, and the whole dish was resplendently sweet and winterishly moreish, the green yellow of the fennel counterpointed by the rich red of the gravy.

Like any casserole, volumes and weights depend on how many you are cooking for I used two bulbs of fennel to one shank and a 15 ounce can of tomatoes, but had to add more water along the way - though there should be lots of liquid as the shank cooks, and a shank will feed a couple of people, three at the very most.